Cobalt-base alloys containing chromium,carbon,tungsten and nickel

ABSTRACT

A COBALT-BASE ALLOY CONTAINING CHROMIUM, CARBON, TUNGSTEN AND NICKEL IS PRODUCED, FOR USE IN JOINING HIGH TEMPERATURE ALLOYS. THE ALLOY HAS A RELATIVELY HIGH CARBON CONTENT AND A RELATIVELY LOW NICKEL CONTENT, SUCH THAT A SUBSTANTIAL INCREASE IN HARDNESS IS EFFECTED WITHOUT SACRIFICE IN TOUGHNESS AND DUCTILITY, AND A BETTER YIELD OF RODS IS OBTAINED WHEN THE ALLOY IS GROUND INTO WELD RODS.

United States Patent Olhce Patented Feb. 16, 1971 3 563 731 COBALT-BASEALLoYs CONTAINING CHRO- MIUM, CARBON, TUNGSTEN AND NICKEL Arthur T.Cape, Monterey, Califi, assignor to Coast Metals, Inc., Little Ferry,N.J., a corporation of Dela- Ware N Drawing. Filed July 28, 1969, Ser.No. 845,582

1 Int. Cl. C220 1 9/ 00 US. Cl. 75171 2 Claims ABSTRACT OF THEDISCLOSURE In the U8. Pat. No. 3,265,494, of James F. Baldwin and ArthurT. Cape, an alloy consisting essentially of chromium, tungsten, nickeland cobalt is described, which is especially useful for high temperatureapplications, such, for example, as joining areas of Waspalloy jetengine turbine blades. A particular feature of the alloy was itsductility and freedom from brittleness which were such that the alloy,when made into weld rods, could be passed through a centerless grinderwithout shattering.

I have found that by increasing the carbon content of such an alloysubstantially, and lowering the nickel content to a narrow range below4%, that an alloy of this type is produced, which is characterized by adesired substantial increase in hardness, without any sacrifice intoughness and ductility, and by the fact that the alloy, when ground ina centerless grinder, to form Weld rods, can be ground down to verysmall diameters ranging from .0625" to .037".

The hardness, in particular, is increased from hardness of 45-48Rockwell C, in the case of the alloy of the aforesaid patent, to ahardness range of 59-65 Rockwell C, in the case of the present alloy.

Alloys made in accordance with this invention have the followinganalysis range, with a preferred alloy of the analysis indicated, thefigures being percentages by weight.

Range, percent Preferred,

percent 1 Maximum.

Alloys within the aforesaid ranges have, as stated, a Rockwell Chardness of 59-65, and can be ground into weld rods, of diameters of.0625".037, with an increased yield of such rods, in comparison withthose of the aforesaid patent.

Having thus described my invention, I claim:

1. An alloy especially adapted for use as a Welding material at hightemperatures, said alloy consisting of carbon 2.5 to 3.0%, chromium 26to 30%, nickel 3.0 to 3.90%, tungsten 18 to 21%, .005 to .1% boron, O to1% silicon, .75 to 1.25% vanadium, O to 1% manganese, 0 to 3% iron, andthe balance essentially all cobalt.

2. 'An alloy especially adapted for use as a Welding material at hightemperatures, said alloy consisting of about 2.87% carbon, about 28.60%chromium, about 3.50% nickel, about 19.25% tungsten, about .05% boron,about .50% silicon, about 1.0% vanadium, about .4% iron, about 0.1%manganese, and about 43.73% cobalt.

References Cited UNITED STATES PATENTS 3,265,494 8/1966 Baldwin et a1.171

RICHARD O. DEAN, Primary Examiner

